US20040262102A1 - Brake structure of traction machine - Google Patents
Brake structure of traction machine Download PDFInfo
- Publication number
- US20040262102A1 US20040262102A1 US10/866,235 US86623504A US2004262102A1 US 20040262102 A1 US20040262102 A1 US 20040262102A1 US 86623504 A US86623504 A US 86623504A US 2004262102 A1 US2004262102 A1 US 2004262102A1
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- United States
- Prior art keywords
- brake
- iron core
- movable iron
- shoes
- drum
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D51/00—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like
- F16D51/10—Brakes with outwardly-movable braking members co-operating with the inner surface of a drum or the like shaped as exclusively radially-movable brake-shoes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
- B66D5/00—Braking or detent devices characterised by application to lifting or hoisting gear, e.g. for controlling the lowering of loads
- B66D5/02—Crane, lift hoist, or winch brakes operating on drums, barrels, or ropes
- B66D5/06—Crane, lift hoist, or winch brakes operating on drums, barrels, or ropes with radial effect
- B66D5/08—Crane, lift hoist, or winch brakes operating on drums, barrels, or ropes with radial effect embodying blocks or shoes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66D—CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS
- B66D5/00—Braking or detent devices characterised by application to lifting or hoisting gear, e.g. for controlling the lowering of loads
- B66D5/02—Crane, lift hoist, or winch brakes operating on drums, barrels, or ropes
- B66D5/24—Operating devices
- B66D5/30—Operating devices electrical
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2121/00—Type of actuator operation force
- F16D2121/18—Electric or magnetic
- F16D2121/20—Electric or magnetic using electromagnets
- F16D2121/22—Electric or magnetic using electromagnets for releasing a normally applied brake
Definitions
- the present invention relates generally to a structure of a brake used in a traction machine or the like. More particularly, the invention is concerned with technology which makes it possible to improve stability of a braking force exerted by a brake of a traction machine or the like as well as stability of ON/OFF actions of the brake and to reduce assembly cost of the brake.
- a rotary shaft of a rotating body is fitted on a bearing which is fitted in the mounting plate.
- the brake drum and the rotating body are both fixed to the rotary shaft so that the brake drum and the rotating body together rotate as a single structure.
- the brake drum rotates with its curved inner surface facing curved outer surfaces of brake shoes of the individual electromagnetic brake units.
- the torque bearing parts for supporting the circumferential end surfaces of the brake shoes protrude from the mounting plate up to and along the brake shoes taking up part of the inner space of the brake drum. Since the torque bearing parts occupy part of the inner space of the brake drum, the total cross-sectional area of the stationary and movable iron cores as viewed along an axial direction of the brake drum is reduced by as much as sectional areas occupied by the torque bearing parts. This reduction in the total cross-sectional area of the stationary and movable iron cores results in a decrease in the attractive force exerted by the stationary iron cores on the respective movable iron cores when electric currents flow through the coils, eventually causing a problem that ON/OFF actions of the brake become unstable.
- the present invention is intended to provide a solution to the aforementioned problems of the prior art. Accordingly, it is an object of the invention to provide such a structure of a brake of a traction machine that can be produced with a reduced manufacturing cost using a simplified assembly procedure.
- a brake structure of a traction machine includes a brake drum which is made rotatable about a shaft disposed on a rotary axis of the traction machine, and an electromagnetic brake unit built in an inner space of the brake drum for braking the rotating brake drum.
- the electromagnetic brake unit includes a plurality of movable iron cores, a plurality of brake shoes located on the outside of the individual movable iron cores and joined thereto by connecting members, and a one-piece formed stationary iron core block. Curved outer surfaces of the brake shoes are positioned face to face with a curved inner surface of the brake drum.
- the one-piece formed stationary iron core block has a plurality of stationary iron core portions joined to the individual movable iron cores via compression springs for forcing the individual brake shoes outward against the curved inner surface of the brake drum via the movable iron cores and the connecting members.
- the brake structure of the invention can be produced by a simple assembly procedure which can provide a reduced manufacturing cost.
- FIG. 1 is a plan view showing a brake structure of a traction machine according to a first embodiment of the invention
- FIGS. 2A and 2B are plan views showing a conventional brake structure
- FIGS. 3A and 3B are fragmentary sectional side views showing a brake structure of a traction machine according to a second embodiment of the invention.
- FIG. 4 is a plan view showing a brake structure of a traction machine according to a third embodiment of the invention.
- FIG. 5 is a plan view showing a brake structure of a traction machine according to a fourth embodiment of the invention.
- FIG. 6 is a plan view showing a brake structure of a traction machine according to a fifth embodiment of the invention.
- FIG. 7 is a plan view showing a brake structure of a traction machine according to a sixth embodiment of the invention.
- FIG. 1 is a plan view showing a structure of a brake of a traction machine according to a first embodiment of the invention.
- the brake structure includes a cylindrical brake drum 2 which is fixedly attached to a rotating body of the traction machine and made rotatable about a central axis of a shaft 17 extending from a later-described housing 14 as well as an electromagnetic brake unit 1 disposed in an inner space of the brake drum 2 .
- the electromagnetic brake unit 1 fixed in a nonrotatable manner includes a pair of movable iron cores 4 and a one-piece formed stationary iron core block 15 .
- the stationary iron core block 15 has a pair of stationary iron core portions facing the individual movable iron cores 4 .
- the brake drum 2 is mounted on the shaft 17 with a bearing placed in between so that the brake drum 2 can rotate about the shaft 17 .
- the electromagnetic brake unit 1 further includes a pair of brake shoes 5 of which curved outer surfaces are disposed face to face with a curved inner surface of the brake drum 2 .
- Each of the brake shoes 5 is fixed to the movable iron core 4 by means of two each connecting members 8 and shoe supports 9 .
- compression springs 12 between the one-piece formed stationary iron core block 15 and each movable iron core 4 .
- the compression springs 12 force the two brake shoes 5 against the curved inner surface of the brake drum 2 to stop rotation of the brake drum 2 .
- the housing 14 is located at one end of the shaft 17 which constitutes an integral part of the housing 14 .
- the housing 14 has on its inside multiple arc-shaped guiding parts 16 disposed along the curved inner surface of the brake drum 2 .
- the guiding parts 16 are located such that circumferential end surfaces of each brake shoe 5 are positioned face to face with circumferential end surfaces of the guiding parts 16 as illustrated.
- the circumferential end surfaces of the guiding parts 16 bear a torque exerted by the rotating brake drum 2 to prevent breakage of the connecting members 8 by supporting the circumferential end surfaces of the brake shoes 5 .
- the brake shoes 5 and the guiding parts 16 are relatively positioned in such a manner that there are formed gaps measuring a few tens of micrometers between the facing circumferential end surfaces of the brake shoes 5 and the guiding parts 16 for bearing the torque, although relative positioning accuracy required varies depending on the size of the connecting members 8 .
- the two stationary iron core portions are formed as integral parts of the single stationary iron core block 15 as stated above, it is possible to produce the brake by a simple assembly procedure which can provide a reduced manufacturing cost.
- the one-piece formed stationary iron core block 15 includes the two stationary iron core portions as integral parts thereof and the electromagnetic brake unit 1 is assembled into the housing 14 when the shaft 17 extending from the housing 14 is fitted into the hole 18 formed in the stationary iron core block 15 .
- the electromagnetic brake unit 1 is assembled into the housing 14 when the shaft 17 extending from the housing 14 is fitted into the hole 18 formed in the stationary iron core block 15 .
- FIG. 2A is a plan view showing the aforementioned conventional brake structure
- FIG. 2B is an enlarged plan view showing one of brake shoe portions of the conventional brake structure.
- a pair of electromagnetic brake units 1 is fixed to a mounting plate 20 by means of fixing screws. If the central position of the two electromagnetic brake units 1 is offset from the center of a brake drum 2 in a vertical direction by a small amount as shown by arrows in FIG. 2A due to backlash between external threads formed on the fixing screws and internal threads that mate with the external threads, or for other reasons, brake shoes 5 would be displaced from their correct positions as shown in FIG. 2B, for instance. Should this situation occur, there will arise a problem that the brake shoes 5 are Lorced against the brake drum 2 under unbalanced pressure, causing a reduction in braking force or slippage of the brake shoes 5 .
- the electromagnetic brake unit 1 is precisely positioned as the shaft 17 of the housing 14 is fitted into the hole 18 formed in the one-piece formed stationary iron core block 15 , so that the brake shoes 5 are not displaced as shown in FIGS. 2A and 2B. It is understood from the foregoing that the brake structure of the embodiment allows easy positioning of the electromagnetic brake unit 1 and produces a stable braking force.
- the electromagnetic brake unit 1 can occupy a larger portion of the inner space of the brake drum 2 , producing thereby stable ON/OFF actions of the brake.
- the arc-shaped guiding parts 16 are provided on the inside of the housing 14 and not on the brake drum 2 . Therefore, after fitting the shaft 17 of the housing 14 into the hole 18 formed in the one-piece formed stationary iron core block 15 , the gaps between the circumferential end surfaces of the brake shoes 5 and the facing circumferential end surfaces of the guiding parts 16 can be easily adjusted by turning the one-piece formed stationary iron core block 15 . This makes it possible to reduce manufacturing cost incurred particularly in assembling the brake.
- the circumferential end surfaces of the guiding parts 16 can be positioned creating small gaps from the circumferential end surfaces of the brake shoes 5 , it is possible to reduce the amount of flexing (bending) of the connecting members 8 . Therefore, the diameter of the connecting members 8 can be reduced and this makes it possible to cut material and machining costs.
- the earlier-mentioned conventional brake structure includes torque bearing parts formed on the mounting plate 20
- the arc-shaped guiding parts 16 are disposed along the curved inner surface of the brake drum 2 inside the housing 14 in the present embodiment.
- This brake structure of the embodiment makes it possible to efficiently use the inner surface of the brake drum 2 and stabilize the ON/OFF actions of the brake. This is because facing surface areas of the one-piece formed stationary iron core block 15 and the movable iron cores 4 can be increased so that the stationary iron core portions of the stationary iron core block 15 exert a large attractive force on the respective movable iron cores 4 .
- the brake structure of the embodiment makes it possible to decrease the number of turns of coils 13 which are embedded in the stationary iron core portions of the one-piece formed stationary iron core block 15 . This results in a reduction in the cost of production of the coils 13 .
- the stationary iron core block 15 While the one-piece formed stationary iron core block 15 is fixed to the housing 14 by fixing the shaft 17 in the hole 18 formed in the stationary iron core block 15 by shrink fit or expansion fit, the stationary iron core block 15 may be fixed to the housing 14 by bolt joints.
- FIG. 3A is a fragmentary sectional side view showing a structure of a brake adapted to a traction machine according to a second embodiment of the invention
- FIG. 3B is an enlarged fragmentary sectional side view of the brake structure of the second embodiment, in which elements identical or similar to those of the first embodiment are designated by the same reference numerals.
- a flange 19 at a basal part of the shaft 17 extending from the housing 14 , the flange 19 having a surface perpendicular to the central axis of the shaft 17 .
- the one-piece formed stationary iron core block 15 is placed against the surface perpendicular to the central axis of the shaft 17 and fixed to the housing 14 by bolts 21 as shown in FIG. 3A.
- the stationary iron core block 15 When the one-piece formed stationary iron core block 15 is fixed to the housing 14 , the stationary iron core block 15 is forced tight against the surface perpendicular to the central axis of the shaft 17 .
- the stationary iron core block 15 becomes exactly at right angles to the shaft 17 so that the electromagnetic brake unit 1 will not be installed at a slant with respect to the central axis of the shaft 17 as shown by broken lines in FIG. 3B.
- the brake shoes 5 can therefore be forced against the brake drum 2 without creating irregular gaps therebetween. Consequently, the brake structure of the embodiment produces a large braking force.
- FIG. 4 is a plan view showing a structure of a brake of a traction machine according to a third embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- each brake shoe 5 As each brake shoe 5 is supported by one each shoe support 9 and connecting member 8 , the brake shoes 5 can easily rotate, or swivel, in circumferential directions along the curved inner surface of the brake drum 2 and in a plane containing the central axis of the shaft 17 . Even when a disturbance occurs to normal functioning of the brake, such as biting of dust or dirt between the brake drum 2 and the brake shoes 5 , abnormal gaps are not created between the brake drum 2 and the brake shoes 5 due to swivel action of the brake shoes 5 . Accordingly, the brake structure of this embodiment helps maintain stable contact between the brake drum 2 and the brake shoes 5 without creating irregular gaps and produce a specific level of braking force even in the presence of undesirable disturbances.
- FIG. 5 is a plan view showing a structure of a brake of a traction machine according to a fourth embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- the brake structure of the fourth embodiment is characterized in that there are provided at least three each movable iron cores 4 and brake shoes 5 .
- the brake structure actually includes six each movable iron cores 4 and brake shoes 5 in the illustrated example of FIG. 5. Since the electromagnetic brake unit 1 is easily assembled in the housing 14 by fitting the shaft 17 into the hole 18 , it is possible to avoid a substantial increase in assembly cost regardless of an increase in the numbers of movable iron cores 4 and brake shoes 5 .
- a notable advantage of the fourth embodiment is that the brake structure can produce an increased braking force as a result of the increase in the number of brake shoes 5 .
- the brake structure of the embodiment helps maintain uniform contact between the brake drum 2 and the brake shoes 5 without creating undesirable gaps and produce a stable braking force regardless of the occurrence of a disturbance, such as biting of dust or dirt between the brake drum 2 and the brake shoes 5 .
- a thin film of water may form between the brake drum 2 and the brake shoes 5 due to condensation as a result of changes in environmental conditions such as ambient temperature. This can cause slippage of the brake shoes 5 along the inner surface of the brake drum 2 . Since a larger number of brake shoes 5 are provided as illustrated, the brake structure of the present embodiment offers an increased safety factor and produce a stable braking force even in the presence of undesirable disturbances.
- different types of compression springs 12 having different spring constants or different lengths may be fitted in a one-piece formed stationary iron core block 15 to adjust thrusting forces exerted by the compression springs 12 on the individual brake shoes 5 .
- This arrangement makes it possible to regulate the shape of the brake drum 2 in such a manner that the brake drum 2 when deformed will suitably fit the shape of the brake shoes 5 and, as a consequence, the brake structure produces an increased braking force.
- FIG. 6 is a plan view showing a structure of a brake of a traction machine according to a fifth embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- each brake shoe 5 is connected to the corresponding movable iron core 4 by two each shoe supports 9 and connecting members 8 in the brake structure of the fourth embodiment, each brake shoe 5 is supported by a single shoe support 9 joined to the movable iron core 4 by a single connecting member 8 in the brake structure of the fifth embodiment illustrated in FIG. 6.
- each brake shoe 5 As each brake shoe 5 is supported by one each shoe support 9 and connecting member 8 , the brake shoes 5 can easily rotate, or swivel, in circumferential directions along the curved inner surface of the brake drum 2 and in a plane containing the central axis of the shaft 17 . Even when a disturbance occurs to normal functioning of the brake, such as biting of dust or dirt between the brake drum 2 and the brake shoes 5 , abnormal gaps are not created between the brake drum 2 and the brake shoes 5 due to swivel action of the brake shoes 5 . Accordingly, the brake structure of this embodiment helps ensure stable contact between the brake drum 2 and the brake shoes 5 without creating irregular gaps and produce a specific level of braking force even in the presence of undesirable disturbances.
- FIG. 7 is a plan view showing a structure of a brake of a traction machine according to a sixth embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- the compression springs 12 of different types are used so that the brake drum 2 when deformed will suitably fit the shape of the brake shoes 5 .
- the brake structure of the sixth embodiment employs the same type of compression springs 12 to apply thrusting forces to the brake shoes 5 to force them against the brake drum 2 .
- the individual brake shoes 5 are supported by varying numbers of shoe supports 9 and connecting members 8 as illustrated in FIG. 7.
- some (four in FIG. 7) of the brake shoes 5 are supported by one each shoe support 9 and connecting member 8 while the other are supported by two each shoe supports 9 and connecting members 8 .
- the amount of deformation of portions of the brake drum 2 forced by the brake shoes 5 supported by one each shoe support 9 and connecting member 8 is large, whereas the amount of deformation of portions of the brake drum 2 forced by the brake shoes 5 supported by two each shoe supports 9 and connecting members 8 is small.
- the number of shoe supports 9 and connecting members 8 supporting the individual brake shoes 5 may be varied as appropriate so that the brake drum 2 will deform (expand) to suitably fit the shape of the brake shoes 5 . Accordingly, the brake structure of this embodiment helps ensure stable contact between the brake drum 2 and the brake shoes 5 without creating irregular gaps and produce an increased braking force.
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Abstract
A brake structure of a traction machine includes a brake drum which is made rotatable about a shaft disposed on a rotary axis of the traction machine, and an electromagnetic brake unit built in an inner space of the brake drum. The electromagnetic brake unit includes a plurality of movable iron cores, a plurality of brake shoes located on the outside of the individual movable iron cores and joined thereto by connecting members, the brake shoes having curved outer surfaces facing a curved inner surface of the brake drum, and a one-piece formed stationary iron core block. The one-piece formed stationary iron core block has a plurality of stationary iron core portions joined to the individual movable iron cores via compression springs for forcing the individual brake shoes against the curved inner surface of the brake drum via the movable iron cores and the connecting members.
Description
- 1. Field of the Invention
- The present invention relates generally to a structure of a brake used in a traction machine or the like. More particularly, the invention is concerned with technology which makes it possible to improve stability of a braking force exerted by a brake of a traction machine or the like as well as stability of ON/OFF actions of the brake and to reduce assembly cost of the brake.
- 2. Description of the Background Art
- Most of conventional traction machines employ an internal expanding brake structure. Typically, an internal expanding brake includes a pair of electromagnetic brake units fixed to a mounting plate, the electromagnetic brake units being disposed in an inner space of a brake drum.
- A rotary shaft of a rotating body is fitted on a bearing which is fitted in the mounting plate. The brake drum and the rotating body are both fixed to the rotary shaft so that the brake drum and the rotating body together rotate as a single structure.
- The brake drum rotates with its curved inner surface facing curved outer surfaces of brake shoes of the individual electromagnetic brake units.
- Each of the electromagnetic brake units includes a stationary iron core on which a coil is wound and a movable iron core which is caused to move in a radial direction of the brake drum by an attractive force exerted by the stationary iron core. The brake shoe is attached to an outer end of the movable iron core via connecting members.
- There are disposed compression springs between the stationary iron core and the movable iron core. These compression springs exert thrusting forces on the stationary iron core of each electromagnetic brake unit to force the brake shoes against the curved inner surface of the brake drum to brake the rotating body. When the coils of the electromagnetic brake units are excited, the stationary iron cores exert the attractive force on the respective movable iron cores to separate the brake shoes from the brake drum. Consequently, braking forces exerted by the brake shoes are released to allow the rotating body to rotate.
- When braking the rotating body, the brake shoes forced against the brake drum receive a torque (turning force) exerted by the rotating brake drum in a rotating direction thereof. The torque thus exerted on each brake shoe could cause eventual breakage of the connecting members. An arrangement for avoiding breakage of the connecting members is disclosed in Japanese Laid-open Patent Publication No. 2002-303341, for example. According to the arrangement of the Publication, there are formed torque bearing parts protruding from the mounting plate up to and along both circumferential end surfaces of each brake shoe. The torque bearing parts act against the torque exerted on the brake shoes by supporting the circumferential end surfaces of the individual brake shoes.
- In the aforementioned internal expanding brake structure of the conventional traction machines, the two separate electromagnetic brake units are fixed to the mounting plate. For this reason, there is always a possibility that the two electromagnetic brake units are relatively offset when installed. More specifically, a central position of the two electromagnetic brake units fixed to the mounting plate could be offset from the center of the brake drum in a particular radial direction of the brake drum. Such a displacement of the electromagnetic brake units could produce uneven contact surface pressures between the brake drum and the brake shoes resulting in a reduction in the braking force produced by the brake structure.
- The torque bearing parts for supporting the circumferential end surfaces of the brake shoes protrude from the mounting plate up to and along the brake shoes taking up part of the inner space of the brake drum. Since the torque bearing parts occupy part of the inner space of the brake drum, the total cross-sectional area of the stationary and movable iron cores as viewed along an axial direction of the brake drum is reduced by as much as sectional areas occupied by the torque bearing parts. This reduction in the total cross-sectional area of the stationary and movable iron cores results in a decrease in the attractive force exerted by the stationary iron cores on the respective movable iron cores when electric currents flow through the coils, eventually causing a problem that ON/OFF actions of the brake become unstable.
- Another problem of the aforementioned conventional brake structure is that the torque bearing parts need to be formed into a rather complicated structure which incurs an increase in manufacturing cost.
- The present invention is intended to provide a solution to the aforementioned problems of the prior art. Accordingly, it is an object of the invention to provide such a structure of a brake of a traction machine that can be produced with a reduced manufacturing cost using a simplified assembly procedure.
- It is another object of the invention to provide such a structure of a brake of a traction machine that makes it possible to produce a stable braking force by stabilizing contact surface pressures between a brake drum and brake shoes.
- It is still another object of the invention to provide such a structure of a brake of a traction machine that makes it possible to produce stable ON/OFF actions of the brake with stationary and movable iron cores occupying a larger portion of an inner space of a brake drum.
- According to the invention, a brake structure of a traction machine includes a brake drum which is made rotatable about a shaft disposed on a rotary axis of the traction machine, and an electromagnetic brake unit built in an inner space of the brake drum for braking the rotating brake drum. The electromagnetic brake unit includes a plurality of movable iron cores, a plurality of brake shoes located on the outside of the individual movable iron cores and joined thereto by connecting members, and a one-piece formed stationary iron core block. Curved outer surfaces of the brake shoes are positioned face to face with a curved inner surface of the brake drum. The one-piece formed stationary iron core block has a plurality of stationary iron core portions joined to the individual movable iron cores via compression springs for forcing the individual brake shoes outward against the curved inner surface of the brake drum via the movable iron cores and the connecting members.
- The brake structure of the invention can be produced by a simple assembly procedure which can provide a reduced manufacturing cost.
- These and other objects, features and advantages of the invention will become more apparent upon reading the following detailed description along with the accompanying drawings.
- FIG. 1 is a plan view showing a brake structure of a traction machine according to a first embodiment of the invention;
- FIGS. 2A and 2B are plan views showing a conventional brake structure;
- FIGS. 3A and 3B are fragmentary sectional side views showing a brake structure of a traction machine according to a second embodiment of the invention;
- FIG. 4 is a plan view showing a brake structure of a traction machine according to a third embodiment of the invention;
- FIG. 5 is a plan view showing a brake structure of a traction machine according to a fourth embodiment of the invention;
- FIG. 6 is a plan view showing a brake structure of a traction machine according to a fifth embodiment of the invention; and
- FIG. 7 is a plan view showing a brake structure of a traction machine according to a sixth embodiment of the invention.
- FIG. 1 is a plan view showing a structure of a brake of a traction machine according to a first embodiment of the invention.
- Referring to FIG. 1, the brake structure includes a
cylindrical brake drum 2 which is fixedly attached to a rotating body of the traction machine and made rotatable about a central axis of ashaft 17 extending from a later-describedhousing 14 as well as anelectromagnetic brake unit 1 disposed in an inner space of thebrake drum 2. Theelectromagnetic brake unit 1 fixed in a nonrotatable manner includes a pair ofmovable iron cores 4 and a one-piece formed stationaryiron core block 15. The stationaryiron core block 15 has a pair of stationary iron core portions facing the individualmovable iron cores 4. - The
brake drum 2 is mounted on theshaft 17 with a bearing placed in between so that thebrake drum 2 can rotate about theshaft 17. - There is formed a
hole 18 at the center of the one-piece formed stationaryiron core block 15 and theshaft 17 is firmly fitted into thishole 18 by shrink fit or expansion fit to assemble theelectromagnetic brake unit 1 in an inner space of thehousing 14 as illustrated in FIG. 1. - The
electromagnetic brake unit 1 further includes a pair ofbrake shoes 5 of which curved outer surfaces are disposed face to face with a curved inner surface of thebrake drum 2. Each of thebrake shoes 5 is fixed to themovable iron core 4 by means of two each connectingmembers 8 and shoe supports 9. - There are disposed compression springs12 between the one-piece formed stationary
iron core block 15 and eachmovable iron core 4. The compression springs 12 force the twobrake shoes 5 against the curved inner surface of thebrake drum 2 to stop rotation of thebrake drum 2. - The
housing 14 is located at one end of theshaft 17 which constitutes an integral part of thehousing 14. Thehousing 14 has on its inside multiple arc-shaped guidingparts 16 disposed along the curved inner surface of thebrake drum 2. The guidingparts 16 are located such that circumferential end surfaces of eachbrake shoe 5 are positioned face to face with circumferential end surfaces of the guidingparts 16 as illustrated. When thebrake shoes 5 are forced against therotating brake drum 2, the circumferential end surfaces of the guidingparts 16 bear a torque exerted by therotating brake drum 2 to prevent breakage of the connectingmembers 8 by supporting the circumferential end surfaces of thebrake shoes 5. - To prevent breakage of the connecting
members 8, thebrake shoes 5 and the guidingparts 16 are relatively positioned in such a manner that there are formed gaps measuring a few tens of micrometers between the facing circumferential end surfaces of thebrake shoes 5 and the guidingparts 16 for bearing the torque, although relative positioning accuracy required varies depending on the size of the connectingmembers 8. - Since the two stationary iron core portions are formed as integral parts of the single stationary
iron core block 15 as stated above, it is possible to produce the brake by a simple assembly procedure which can provide a reduced manufacturing cost. - According to the embodiment, the one-piece formed stationary
iron core block 15 includes the two stationary iron core portions as integral parts thereof and theelectromagnetic brake unit 1 is assembled into thehousing 14 when theshaft 17 extending from thehousing 14 is fitted into thehole 18 formed in the stationaryiron core block 15. As is apparent from the foregoing discussion, it is not necessary to affix separate electromagnetic brake units to a mounting plate in the aforementioned brake structure of the embodiment unlike the case of the earlier-described conventional internal expanding brake structure. - To produce a satisfactory level of braking force with the brake structure of the embodiment, it is desirable that the two
movable iron cores 4 move exactly in radial directions of thebrake drum 2 and radially press against the curved inner surface of thebrake drum 2. - FIG. 2A is a plan view showing the aforementioned conventional brake structure, and FIG. 2B is an enlarged plan view showing one of brake shoe portions of the conventional brake structure. Referring to FIG. 2A, a pair of
electromagnetic brake units 1 is fixed to a mountingplate 20 by means of fixing screws. If the central position of the twoelectromagnetic brake units 1 is offset from the center of abrake drum 2 in a vertical direction by a small amount as shown by arrows in FIG. 2A due to backlash between external threads formed on the fixing screws and internal threads that mate with the external threads, or for other reasons,brake shoes 5 would be displaced from their correct positions as shown in FIG. 2B, for instance. Should this situation occur, there will arise a problem that thebrake shoes 5 are Lorced against thebrake drum 2 under unbalanced pressure, causing a reduction in braking force or slippage of thebrake shoes 5. - In the brake structure of the present embodiment, the
electromagnetic brake unit 1 is precisely positioned as theshaft 17 of thehousing 14 is fitted into thehole 18 formed in the one-piece formed stationaryiron core block 15, so that thebrake shoes 5 are not displaced as shown in FIGS. 2A and 2B. It is understood from the foregoing that the brake structure of the embodiment allows easy positioning of theelectromagnetic brake unit 1 and produces a stable braking force. - Since the
housing 14 has on its inside the arc-shaped guidingparts 16 located along the curved inner surface of thebrake drum 2, theelectromagnetic brake unit 1 can occupy a larger portion of the inner space of thebrake drum 2, producing thereby stable ON/OFF actions of the brake. - In this embodiment, the arc-shaped guiding
parts 16 are provided on the inside of thehousing 14 and not on thebrake drum 2. Therefore, after fitting theshaft 17 of thehousing 14 into thehole 18 formed in the one-piece formed stationaryiron core block 15, the gaps between the circumferential end surfaces of thebrake shoes 5 and the facing circumferential end surfaces of the guidingparts 16 can be easily adjusted by turning the one-piece formed stationaryiron core block 15. This makes it possible to reduce manufacturing cost incurred particularly in assembling the brake. - Furthermore, since the circumferential end surfaces of the guiding
parts 16 can be positioned creating small gaps from the circumferential end surfaces of thebrake shoes 5, it is possible to reduce the amount of flexing (bending) of the connectingmembers 8. Therefore, the diameter of the connectingmembers 8 can be reduced and this makes it possible to cut material and machining costs. - While the earlier-mentioned conventional brake structure includes torque bearing parts formed on the mounting
plate 20, the arc-shaped guidingparts 16 are disposed along the curved inner surface of thebrake drum 2 inside thehousing 14 in the present embodiment. This brake structure of the embodiment makes it possible to efficiently use the inner surface of thebrake drum 2 and stabilize the ON/OFF actions of the brake. This is because facing surface areas of the one-piece formed stationaryiron core block 15 and themovable iron cores 4 can be increased so that the stationary iron core portions of the stationaryiron core block 15 exert a large attractive force on the respectivemovable iron cores 4. - Moreover, the brake structure of the embodiment makes it possible to decrease the number of turns of
coils 13 which are embedded in the stationary iron core portions of the one-piece formed stationaryiron core block 15. This results in a reduction in the cost of production of thecoils 13. - While the one-piece formed stationary
iron core block 15 is fixed to thehousing 14 by fixing theshaft 17 in thehole 18 formed in the stationaryiron core block 15 by shrink fit or expansion fit, the stationaryiron core block 15 may be fixed to thehousing 14 by bolt joints. - FIG. 3A is a fragmentary sectional side view showing a structure of a brake adapted to a traction machine according to a second embodiment of the invention, and FIG. 3B is an enlarged fragmentary sectional side view of the brake structure of the second embodiment, in which elements identical or similar to those of the first embodiment are designated by the same reference numerals.
- In this embodiment, there is formed a
flange 19 at a basal part of theshaft 17 extending from thehousing 14, theflange 19 having a surface perpendicular to the central axis of theshaft 17. The one-piece formed stationaryiron core block 15 is placed against the surface perpendicular to the central axis of theshaft 17 and fixed to thehousing 14 bybolts 21 as shown in FIG. 3A. - The provision of the
bolts 21 allows easier positioning of the stationaryiron core block 15 with respect to thehousing 14, contributing thereby to improving the yield of brakes in the manufacture of thereof. - When the one-piece formed stationary
iron core block 15 is fixed to thehousing 14, the stationaryiron core block 15 is forced tight against the surface perpendicular to the central axis of theshaft 17. Thus, the stationaryiron core block 15 becomes exactly at right angles to theshaft 17 so that theelectromagnetic brake unit 1 will not be installed at a slant with respect to the central axis of theshaft 17 as shown by broken lines in FIG. 3B. Thebrake shoes 5 can therefore be forced against thebrake drum 2 without creating irregular gaps therebetween. Consequently, the brake structure of the embodiment produces a large braking force. - FIG. 4 is a plan view showing a structure of a brake of a traction machine according to a third embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- While each
brake shoe 5 is connected to the correspondingmovable iron core 4 by a pair of shoe supports 9 in the brake structure of the first embodiment, eachbrake shoe 5 is supported by asingle shoe support 9 joined to themovable iron core 4 by a single connectingmember 8 in the brake structure of the third embodiment illustrated in FIG. 4. - As each
brake shoe 5 is supported by one eachshoe support 9 and connectingmember 8, thebrake shoes 5 can easily rotate, or swivel, in circumferential directions along the curved inner surface of thebrake drum 2 and in a plane containing the central axis of theshaft 17. Even when a disturbance occurs to normal functioning of the brake, such as biting of dust or dirt between thebrake drum 2 and thebrake shoes 5, abnormal gaps are not created between thebrake drum 2 and thebrake shoes 5 due to swivel action of thebrake shoes 5. Accordingly, the brake structure of this embodiment helps maintain stable contact between thebrake drum 2 and thebrake shoes 5 without creating irregular gaps and produce a specific level of braking force even in the presence of undesirable disturbances. - FIG. 5 is a plan view showing a structure of a brake of a traction machine according to a fourth embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- The brake structures of the aforementioned first to third embodiments include two each
movable iron cores 4 andbrake shoes 5. - The brake structure of the fourth embodiment is characterized in that there are provided at least three each
movable iron cores 4 andbrake shoes 5. The brake structure actually includes six eachmovable iron cores 4 andbrake shoes 5 in the illustrated example of FIG. 5. Since theelectromagnetic brake unit 1 is easily assembled in thehousing 14 by fitting theshaft 17 into thehole 18, it is possible to avoid a substantial increase in assembly cost regardless of an increase in the numbers ofmovable iron cores 4 andbrake shoes 5. - A notable advantage of the fourth embodiment is that the brake structure can produce an increased braking force as a result of the increase in the number of
brake shoes 5. - If the number of
brake shoes 5 disposed inside thebrake drum 2 is small, thebrake drum 2 may deform into an elliptical shape creating irregular gaps between thebrake drum 2 and thebrake shoes 5 when thebrake shoes 5 are forced against thebrake drum 2. Such deformation of thebrake drum 2 could result in a reduction in the braking force. If a larger number ofbrake shoes 5 are arranged along the curved inner surface of thebrake drum 2 as shown in the example of FIG. 5, thebrake drum 2 remains in an annular shape even when pressed outward by thebrake shoes 5. Thus, the brake structure of the embodiment helps maintain uniform contact between thebrake drum 2 and thebrake shoes 5 without creating undesirable gaps and produce a stable braking force regardless of the occurrence of a disturbance, such as biting of dust or dirt between thebrake drum 2 and thebrake shoes 5. - Generally, a thin film of water may form between the
brake drum 2 and thebrake shoes 5 due to condensation as a result of changes in environmental conditions such as ambient temperature. This can cause slippage of thebrake shoes 5 along the inner surface of thebrake drum 2. Since a larger number ofbrake shoes 5 are provided as illustrated, the brake structure of the present embodiment offers an increased safety factor and produce a stable braking force even in the presence of undesirable disturbances. - In addition, different types of compression springs12 having different spring constants or different lengths may be fitted in a one-piece formed stationary
iron core block 15 to adjust thrusting forces exerted by the compression springs 12 on theindividual brake shoes 5. This arrangement makes it possible to regulate the shape of thebrake drum 2 in such a manner that thebrake drum 2 when deformed will suitably fit the shape of thebrake shoes 5 and, as a consequence, the brake structure produces an increased braking force. - FIG. 6 is a plan view showing a structure of a brake of a traction machine according to a fifth embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- While each
brake shoe 5 is connected to the correspondingmovable iron core 4 by two each shoe supports 9 and connectingmembers 8 in the brake structure of the fourth embodiment, eachbrake shoe 5 is supported by asingle shoe support 9 joined to themovable iron core 4 by a single connectingmember 8 in the brake structure of the fifth embodiment illustrated in FIG. 6. - As each
brake shoe 5 is supported by one eachshoe support 9 and connectingmember 8, thebrake shoes 5 can easily rotate, or swivel, in circumferential directions along the curved inner surface of thebrake drum 2 and in a plane containing the central axis of theshaft 17. Even when a disturbance occurs to normal functioning of the brake, such as biting of dust or dirt between thebrake drum 2 and thebrake shoes 5, abnormal gaps are not created between thebrake drum 2 and thebrake shoes 5 due to swivel action of thebrake shoes 5. Accordingly, the brake structure of this embodiment helps ensure stable contact between thebrake drum 2 and thebrake shoes 5 without creating irregular gaps and produce a specific level of braking force even in the presence of undesirable disturbances. - FIG. 7 is a plan view showing a structure of a brake of a traction machine according to a sixth embodiment of the invention, in which elements identical or similar to those of the foregoing embodiments are designated by the same reference numerals.
- In the aforementioned fourth embodiment, the compression springs12 of different types (different spring constants or lengths) are used so that the
brake drum 2 when deformed will suitably fit the shape of thebrake shoes 5. - By comparison, the brake structure of the sixth embodiment employs the same type of compression springs12 to apply thrusting forces to the
brake shoes 5 to force them against thebrake drum 2. However, theindividual brake shoes 5 are supported by varying numbers of shoe supports 9 and connectingmembers 8 as illustrated in FIG. 7. - Provided that the
individual brake shoes 5 are pressed against thebrake drum 2 by the same thrusting force, aparticular brake shoe 5 supported by a larger number of shoe supports 9 and connectingmembers 8 produces a reduced amount of maximum deformation of thebrake drum 2 since the thrusting force (or a load exerted on the brake drum 2) is distributed over the circumferential length of thebrake shoe 5. - In the illustrated example of the brake structure of the sixth embodiment, some (four in FIG. 7) of the
brake shoes 5 are supported by one eachshoe support 9 and connectingmember 8 while the other are supported by two each shoe supports 9 and connectingmembers 8. In this arrangement, the amount of deformation of portions of thebrake drum 2 forced by thebrake shoes 5 supported by one eachshoe support 9 and connectingmember 8 is large, whereas the amount of deformation of portions of thebrake drum 2 forced by thebrake shoes 5 supported by two each shoe supports 9 and connectingmembers 8 is small. In this embodiment, the number of shoe supports 9 and connectingmembers 8 supporting theindividual brake shoes 5 may be varied as appropriate so that thebrake drum 2 will deform (expand) to suitably fit the shape of thebrake shoes 5. Accordingly, the brake structure of this embodiment helps ensure stable contact between thebrake drum 2 and thebrake shoes 5 without creating irregular gaps and produce an increased braking force.
Claims (8)
1. A brake structure of a traction machine, said brake structure comprising:
a brake drum which is made rotatable about a shaft disposed on a rotary axis of the traction machine; and
an electromagnetic brake unit built in an inner space of the brake drum for braking the rotating brake drum, the electromagnetic brake unit including:
a plurality of movable iron cores;
a plurality of brake shoes located on the outside of the individual movable iron cores and joined thereto by connecting members, the brake shoes having curved outer surfaces positioned face to face with a curved inner surface of the brake drum; and
a one-piece formed stationary iron core block having a plurality of stationary iron core portions joined to the individual movable iron cores via compression springs for forcing the individual brake shoes outward against the curved inner surface of the brake drum via the movable iron cores and the connecting members.
2. The brake structure according to claim 1 , wherein the one-piece formed stationary iron core block has a hole in which the shaft is fitted.
3. The brake structure according to claim 1 , wherein the electromagnetic brake unit includes at least three each movable iron cores and brake shoes.
4. The brake structure according to claim 1 further comprising guiding parts disposed along the curved inner surface of the brake drum, the guiding parts having end surfaces which face circumferential end surfaces of the brake shoes, wherein the end surfaces of the guiding parts bear a torque exerted on the brake shoes by the rotating brake drum.
5. The brake structure according to claim 1 , wherein each of the brake shoes is joined to the corresponding movable iron core by one connecting member.
6. The brake structure according to claim 1 , wherein the compression springs are a combination of springs having different properties.
7. The brake structure according to claim 1 , wherein the brake shoes are joined to the movable iron cores by varying numbers of connecting members.
8. The brake structure according to claim 1 further comprising a flange having a surface perpendicular to a central axis of the shaft, wherein the one-piece formed stationary iron core block is placed against the surface perpendicular to the central axis of the shaft and fixed to the flange.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2003-183651 | 2003-06-27 | ||
JP2003183651A JP3947497B2 (en) | 2003-06-27 | 2003-06-27 | Brake structure of hoisting machine |
Publications (2)
Publication Number | Publication Date |
---|---|
US20040262102A1 true US20040262102A1 (en) | 2004-12-30 |
US7073640B2 US7073640B2 (en) | 2006-07-11 |
Family
ID=33535353
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/866,235 Expired - Fee Related US7073640B2 (en) | 2003-06-27 | 2004-06-14 | Brake structure of traction machine |
Country Status (5)
Country | Link |
---|---|
US (1) | US7073640B2 (en) |
JP (1) | JP3947497B2 (en) |
KR (1) | KR100596281B1 (en) |
CN (1) | CN1322248C (en) |
DE (1) | DE102004030830B4 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006109180A1 (en) * | 2005-04-13 | 2006-10-19 | Automotive Products Italia (Sv) S.R.L. | Drum brake |
EP1897835A1 (en) * | 2005-06-28 | 2008-03-12 | Mitsubishi Denki Kabushiki Kaisha | Brake device for elevator |
CN101160476B (en) * | 2005-04-13 | 2010-05-19 | 汽车产品意大利(Sv)有限责任公司 | Drum brake |
US20150114762A1 (en) * | 2013-10-29 | 2015-04-30 | Kone Corporation | Damping arrangement for damping the opening noise of a machinery brake of an elevator hoisting machine; an elevator hoisting machine, and an elevator |
US20160031674A1 (en) * | 2013-04-24 | 2016-02-04 | Mitsubishi Electric Corporation | Braking apparatus and elevator hoisting machine that uses same |
US20160039637A1 (en) * | 2013-04-24 | 2016-02-11 | Mitsubishi Electric Corporation | Braking apparatus, elevator hoisting machine that uses same, and buffering reaction force adjusting method for a braking apparatus |
CN111350775A (en) * | 2020-03-09 | 2020-06-30 | 袁国华 | Fork truck with automatic brake |
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Publication number | Priority date | Publication date | Assignee | Title |
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JP5210488B2 (en) * | 2005-06-29 | 2013-06-12 | 三菱電機株式会社 | Hoisting machine |
CN100416127C (en) * | 2006-02-13 | 2008-09-03 | 上海三菱电梯有限公司 | Internal expanding electromagnetic braker |
ES2557328T3 (en) * | 2007-06-18 | 2016-01-25 | Inventio Ag | Device and procedure to control a braking device |
JP2011037621A (en) * | 2009-08-18 | 2011-02-24 | Mitsubishi Electric Corp | Brake device for elevator hoisting machine |
CN103080592B (en) * | 2010-09-08 | 2015-07-22 | 三菱电机株式会社 | Braking apparatus, brake lining, method for manufacturing brake lining, and elevator system |
JP5788846B2 (en) * | 2012-09-07 | 2015-10-07 | 株式会社日立製作所 | Elevator hoisting machine and elevator equipped with the elevator hoisting machine |
JP6194204B2 (en) * | 2013-08-08 | 2017-09-06 | 小倉クラッチ株式会社 | Electromagnetic drum brake |
CN104868686B (en) * | 2015-05-25 | 2017-05-10 | 湖州鸿远电机有限公司 | Rapid direct-current brushless motor structure |
CN104868685B (en) * | 2015-05-25 | 2017-08-04 | 湖州鸿远电机有限公司 | A kind of brushless AC motor structure |
CN106321688B (en) * | 2016-11-22 | 2018-05-04 | 重庆凸普科技有限公司 | A kind of electricity cut-off type electromagnet drum brake |
CN107482847B (en) * | 2017-08-28 | 2019-05-24 | 永坤电动卷门机(深圳)有限公司 | Motor and the hydraulic power assembly for using the motor |
CN109027064B (en) * | 2018-07-17 | 2019-12-06 | 长沙学院 | Electrically controlled brake device |
CN109458409B (en) * | 2018-12-30 | 2020-12-29 | 河北百龙汽车配件股份有限公司 | Combined anti-lock brake drum for heavy-duty car |
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CN111776906B (en) * | 2020-06-11 | 2021-12-17 | 上海市建筑科学研究院科技发展有限公司 | Method and device for adjusting action speed of self-resetting progressive overspeed protector |
JP7031776B1 (en) * | 2021-04-09 | 2022-03-08 | 三菱電機株式会社 | Brake device and elevator hoist |
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JP2001343033A (en) * | 2000-03-24 | 2001-12-14 | Shinko Electric Co Ltd | Radial braking or thrust braking type electromagnetic brake and motor with radial braking type electromagnetic brake |
JP3635035B2 (en) | 2001-02-15 | 2005-03-30 | 三陽工業株式会社 | Brake device |
JP2002284486A (en) | 2001-03-22 | 2002-10-03 | Sanyo Kogyo Kk | Hoist gear |
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JP2002362861A (en) | 2001-06-04 | 2002-12-18 | Mitsubishi Electric Corp | Brake device of elevator hoist |
JP4878089B2 (en) | 2001-06-15 | 2012-02-15 | 三菱電機株式会社 | Elevator hoist brakes |
JPWO2003004400A1 (en) * | 2001-07-05 | 2004-10-21 | 三菱電機株式会社 | Elevator hoist and brake device therefor |
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- 2004-06-14 US US10/866,235 patent/US7073640B2/en not_active Expired - Fee Related
- 2004-06-25 CN CNB2004100600717A patent/CN1322248C/en not_active Expired - Lifetime
- 2004-06-25 DE DE102004030830A patent/DE102004030830B4/en not_active Expired - Lifetime
- 2004-06-25 KR KR1020040048057A patent/KR100596281B1/en active IP Right Grant
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US2385459A (en) * | 1943-03-29 | 1945-09-25 | Dumore Company | Electric brake mechanism |
US2467891A (en) * | 1944-07-20 | 1949-04-19 | Star Electric Motor Company | Electromagnetic brake |
US3584710A (en) * | 1968-03-01 | 1971-06-15 | Gunter Frohlich | Electromagnetically releasable drum brake with internal shoes |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2006109180A1 (en) * | 2005-04-13 | 2006-10-19 | Automotive Products Italia (Sv) S.R.L. | Drum brake |
GB2439243A (en) * | 2005-04-13 | 2007-12-19 | Automotive Prod Co Ltd | Drum brake |
CN101160476B (en) * | 2005-04-13 | 2010-05-19 | 汽车产品意大利(Sv)有限责任公司 | Drum brake |
US8607940B2 (en) | 2005-04-13 | 2013-12-17 | Automotive Products Italia (Sv) S.R.L. | Drum brake |
EP1897835A1 (en) * | 2005-06-28 | 2008-03-12 | Mitsubishi Denki Kabushiki Kaisha | Brake device for elevator |
EP1897835A4 (en) * | 2005-06-28 | 2012-10-24 | Mitsubishi Electric Corp | Brake device for elevator |
US20160031674A1 (en) * | 2013-04-24 | 2016-02-04 | Mitsubishi Electric Corporation | Braking apparatus and elevator hoisting machine that uses same |
US20160039637A1 (en) * | 2013-04-24 | 2016-02-11 | Mitsubishi Electric Corporation | Braking apparatus, elevator hoisting machine that uses same, and buffering reaction force adjusting method for a braking apparatus |
US9663325B2 (en) * | 2013-04-24 | 2017-05-30 | Mitsubishi Electric Corporation | Braking apparatus and elevator hoisting machine that uses same |
US9868613B2 (en) * | 2013-04-24 | 2018-01-16 | Mitsubishi Electric Corporation | Braking apparatus, elevator hoisting machine that uses same, and buffering reaction force adjusting method for a braking apparatus |
US20150114762A1 (en) * | 2013-10-29 | 2015-04-30 | Kone Corporation | Damping arrangement for damping the opening noise of a machinery brake of an elevator hoisting machine; an elevator hoisting machine, and an elevator |
CN111350775A (en) * | 2020-03-09 | 2020-06-30 | 袁国华 | Fork truck with automatic brake |
Also Published As
Publication number | Publication date |
---|---|
JP2005016649A (en) | 2005-01-20 |
DE102004030830B4 (en) | 2009-07-23 |
US7073640B2 (en) | 2006-07-11 |
KR20050001444A (en) | 2005-01-06 |
JP3947497B2 (en) | 2007-07-18 |
CN1322248C (en) | 2007-06-20 |
KR100596281B1 (en) | 2006-07-03 |
DE102004030830A1 (en) | 2005-02-10 |
CN1576634A (en) | 2005-02-09 |
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